1. Field
The present disclosure relates to the power consumption of power supplies, and more particularly pertains to a new system for minimizing the power consumption of a device when in the device is powered down while still providing for the possibility of a minimal power flow to the device while the power consumption is being limited.
2. Description of the Prior Art
Transformers are employed for a multitude of devices that require power at a voltage that is less than the voltage at which power is available. For example, common household power is available at approximately 110 to approximately 120 (or more) Volts, and the components of electronic devices often operate at voltages that are less than one-tenth of the household power voltage. As an example, personal computers employ circuitry that utilizes power at voltages much lower than household voltage, such as about 5 volts. The personal computers thus employ transformers that step down the voltage (as well as other circuitry that processes the power into the required characteristics) to the usable voltage level. While some computers, such as desktop computers, employ transformers that are internal to the housing of the computer, other computers, such as laptop or portable computers, utilize transformers that are incorporated into a wall plug (often referred to as a “wall wart”) of the power cord or are integrated into a medial portion of the power cord itself.
The power cords of the devices typically remain plugged into an electrical outlet even when the device is not actively being used, or “powered up” for use, and it is common to leave the power cord for the device, including any transformer integrated into the power cord, connected to the outlet even when the power cord is disconnected from the device. Nevertheless, even through the device may be turned off, or disconnected from the power cord and transformer, the transformer and associated circuitry may continue to consume power from the household power supply so long as the transformer remains in communication with the household power outlet. This small but persistent consumption of power can increase the overall power usage of the house or business and add cost to the power usage, especially when it is considered that a common household will include many such devices for not only operating these devices but also charging batteries that are often incorporated into the devices. However, most users are unaware of the parasitic power consumption and, as a matter of convenience, allow the power cords and transformers to remain plugged into the power outlet during periods of non-use of the device.
Imposing a switch between the transformer and the power outlet would serve to isolate the transformer from the household power supply. Such an approach would require that the transformer be incorporated into the device, which defeats any size or cooling benefits of locating the transformer on the power cord, or would require that the switch be situated in a location inconvenient to the user if the transformer is located on the power cord or on the power plug. In any event, it is often desirable to permit a small amount of power to be available to the device even in the powered-down condition to maintain information in memory, etc., and a switch situated between the transformer and the power outlet would cut off the possibility of that power flow.
It is therefore believed that there exists in the art a need for a system that minimizes the power consumption of a component of a device when in the device is powered down, while still providing for the possibility of a minimal power flow to the device while the power consumption is being limited.